No. 50k for a stupid J-spec Vios is ridiculous.
I bought my second hand Nissan for 54k and I get much much more space than the Vios, bigger engine than the Vios, more comfortable than the Vios, everything better than the Vios. No, not a stupid Sentra.
As for Protons, having really thrashed the Preve, Suprima and Neo in a controlled environment, I can tell you the Neo is one helluva good handling car in stock form. But specifically the R3 variant la. The Suprima and Preve is supremely comfortable for a Proton and very well equipped for the price. To be honest, it only has one competitor - the brand spanking new City which is bloody awesome too. That article will be coming up - we got to do a side by side comparison with the Vios, Almera and Polo sedan. Having driven the Suprima and Preve too, can say I've covered all the competition. City is unbelievably good.
Anyway, 2nd hand cars - second hand car dealers are unscrupulous buggers. So if you do go find one, make sure you do proper research and bring along an expert if necessary. I know of a Civic FD which had colour changed, tyres changed to old tyres, mileage changed, body kit and then sold for 20k more than trade in price.